Hydraulic apparatus



Nair. 3Q, 1948. T. E. RAYMOND 9 HYDRAULIC APPARATUS Filed June 16, 1944 v v :5 Sheets-Sheet 1' m a g I' i% I 0@ c \rrr w 0%: a 1m 3 a $1 INVENTOR THOMAS E.RAYM0ND Wm yam M ATTORNEY NQV. 3Q, I RAYMOND 4 HYDRAULIC APPARATUS Filed June 16, 1944 3 Sheets-Sheet 2' INVENTO THOMAS ERAYMON BY 95mm X/ ATTORNEY T. ERAYMOND HYDRAULIC APPARATUS Q 3 Sheets-Sheet 3 Filed June 16, 1944 INVEN.TOR THOMAS E. PAYMQND W z i m Patented Nov. 30, 1948 HYDRAULIC APPARATUS Thomas E. Raymond, Zanesville, Ohio, assignor to Simplex Engineering Company, Zanesville,

Ohio

Application June 16, 1944, Serial No. 540,605

10 Claims.

This invention relates to hydraulics and is particularly directed to apparatus for producing fluid pressures which may be employed in the operation of machine tools, presses, rams, motors and other hydraulic equipment.

In some machine tools such as presses, shapers, .planers and the like which are operated by hydraulic pressure, a piston, ram or other element -is required to move a considerable distance without exerting appreciable force and then near the termination, of its travel is required to exert a maximum force to perform useful work. During the major portion of travel, only slight power is required to move the piston but when the useful work is to be performed, increased force is necessary. It is an object of this invention to provide a power unit for a machine operating in this manner which power unit has a plurality of pumps for quickly delivering a large quantity of fluid to the piston cylinder at relatively low pressure during the first part of the piston stroke and a smaller quantity of fluid at high pressure during the final stage of the pistons stroke, the unit being so constructed that undue loads will not be applied to the pumps or other parts of the system during the time the high pressure is be ing utilized.

An object of this invention. also is to provide an integral, compact, fluid power unit which may 'be connected in circuit with an article of hydraulic equipment and employed to furnish the motive power for such equipment, the unit being so fabricated that it may be disconnected, bodily removed, serviced and replaced without dismantling the other equipment or the system therefor.

Another object of this invention is to provide a fluid power unit having a prime mover and a plurality of pumps with different volumetric and pressure capacities secured for operation therewith, thepump outlets being in communication so that the flow from both pumps may be utilized in the operation of a piece of mechanism, means also being associated with the pumps to isolate one from the other when certain pressures prevail in the system.

Another object is to provide a fluid power unit having a pair of power operated pumps capable of producing difierent pressures and communicating with a chamber divided by suitable means into' high and low pressure sections and providing the different sections of the chamber with relief means to permit fluid to escape after a predetermined pressure has been reached, the chamber dividing means being so constructed as to permit communication between the low and high pressure section as long as the pressure in the latter does not exceed the pressure in the former, and when a predetermined pressure in the chamber is reached, the relief valve for the low pressure section will operate to prevent the overloading of the low pressure pump; at this time the chamber dividing means will prevent fluid flow from the high tothe low pressure section.

A further object of the invention is to provide a fluid power unit having a motor with a fluid pump at either end connected for operation with the motor and conducting the fluid from the pumps to a manifold from which it may be directed to the point of use, the manifold having means for relieving the load on each pump when the pressure capacity thereof is exceeded and means for preventing the relief of a higher capacity pump through the relief means for a lower capacity pump.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

In the drawings:

Figure 1 is a front elevational view of a hydraulic power unit formed in accordance with the present invention;

Figure 2 is an end elevational view of the unit shown in Figure 1;

Figure 3 is a detailed vertical sectional view taken through a manifold used on the unit shown in Figure 1, the plane of the section being indicated by the line 3-3 of Figure 1; and

Figure 4 is a similar view taken through the manifold and associated mechanism on the plane indicated by the line 4-4 of Figure 3.

Referring more particularly to the drawings, the power unit forming the present invention is designated generally by the numeral 20. This unit includes an electric motor 2|, high and low pressure hydraulic pumps 23 and 22, a reservoir 24, a manifold 25 and a connecting pipe system designated generally by the numeral 2G.

In its preferred form, the unit has a pair of plates 21-21 which are secured to the housing of the motor 2! by screws or other fastening elements 28. The upper edges of the plates 21 are curved to receive the reservoir 24 which may be secured to the plates by welding or other suitable means. In this instance, the reservoir is in the form of a cylindrical tank having one or more plugs 30 in the top through which hydraulic fluid maybe introduced to the reservoir. One end of the tank 24 is provided with an opening which is normally closed by a cap 3! through which tubes 32 and 33 extend, these tubes having their inner ends connected with a cooling coil, not shown. The water or other cooling medium may be supplied to the cooling coil and conducted therefrom through the pipes 32 and 33.

The pumps 22 and 23 are of the type shown in my copending application Serial No. 529,957, filed April 7, 1944, now abandoned, and are attached to the opposite ends of the armature shaft of the motor 2|, mounting collars 34 being employed to support the pumps in alignment with the ends of the armature shaft. These collars are also disclosed in detail in the above mentioned application. They are split and are clamped to bosses 35 and 36 provided on the motor and pump housings through the use of screws 39. The pump shafts are suitably coupled to the ends of the armature shaft. Thus when the armature shaft revolves, both of the pumps will" be revolved at the same rate of speed.

Each end of the reservoir 24 is provided with a cap 31 into which one end of a pipe valve 38 is threaded. The opposite ends of the valves 38 receive elbow members 40 which, in turn, are connected by tubing 4| and couplings 42- with the inlet ports of the pumps 22 and 23. The outlet ports of these pumps are connected with conduits 43 and 44 which extend toward one another and are connected at their proximate ends with the manifold 25. This manifold is secured to a cross brace 45 extending :betWeen the plates 21.

As shown in Figs. 3 and 4, the manifold 25 includes a block like body 46 bored at ea'ch'end to provide chambers 41 and 48;? The chamber 41 includes sections 50 and t which are separated by a valve seat 52. The conduit 43 l'eadi'ng from the low pressure pump 22 is connected, as shown in Fig. 3, with the section 5i of the chamber 41 while conduit 44 leading from the outlet of the high pressure pump 23 communicates with the section 50' of the chamber 41. The outer end of this chamber is closed by a plug 53 which is threaded into the bl'ook'46. This plug 53 has a threaded opening formed therein to receive a stop pin 54 which serves to limit the movement of a ball valve 55 away from the seat 52, this ball valve being normally urged toward 'the' seat by a coil spring 56; Through the provision of the seat and the valve, chambers? 50 and 5| are sep-' arated from one another and communication can only be established therebetween by moving the [ball valve 55' away from theseat '52. This communication will occur only when pressure within chamber 5| is suflic'ient to overcome the combined force of the pressurein chamber 50 and spring 56. By substituting springs with different tensions'for spring 56, the responsiveness of valve 55 may be varied. Ifdesired,this communicationmay be prevented by threading the member 54into the" member 53"until the inner end of the former engages the ball valve 55. Theseparts are sopositionedin one use of the apparatus to be set forth hereafter.

The conduits 43 and 44 are connected with the body 46 at the rear thereof while the front portion of this body is provided with outlet ports 51 and 58 for the reception'of additional conduits 51A and 58A, the former communicating with the low pressure section 5| of the chamber and the latter communicating with the high pressure sec-- tion. These conduits 51A and 5824; are utilized to conduct fluid under high and low pressure from the manifold to any desired Points Of use.

such as fluid motors of the rotary or piston and cylinder type. In some instances, conduit 51A will be connected with one fluid motor while conduit 58A is connected with another. It is also possible to plug the port 51 and utilize the fluid from both high and low pressure pumps in one motor, this fluid being conducted from manifold 25 through pipe 58A.

From the mechanism thus far described, it will be apparent that when motor 2i is in operation, pumps 22 and 23 will deliver fluid to the manifold 25 from which it may be conducted to one or more fluid motors. When the operation is initiated, and the fluid is still at low pressure in the system, fluid from low pressure pump 22 may flow past valve and thus be conducted through both conduits 51A and 58A to the points of use. When a certain pressure, determined by the tension of spring 56, has been built up in chamber 50, this communication between sections 50 and 51 will be terminated and all' fluid from the low pressure pump must pass out of the manifold 25 through conduit 51A or through bypass port 6t and conduit 6!. This conduit 5| connects a chamber 62 formed in a relief valve 63 with the chamber 48 formed in the upper end of the body 45. Chamber 4-8 is connected by pipe 64 with the reservoir 24. Thus whenfluidflows from section 5i through the bypass port 60,- it will be returned to the reservoir 24 for further use.

A second bypass 65 extends: from the section 53 to a chamber 66 formed in a second'relief valve 67. A conduit 68 connects chamber with chamber 48 so that when fluid flows from the section 50 through bypass port 55' to chamber 66, this fluid will also be conducted to the reservoir. When valve 55 is held. against seat 52 and more fluid than the system can utilize is supplied to chamber section 58 by the high pressure pump 23, the excess fluid will be returned to the reservoir through the bypass port 65, conduit 58: and pipe 54.

By providing valves 10 and H for engagement with bypass ports and 65, fluid will be prevented from flowing through these bypass ports until certain predetermined pressures have been reached. As shown in Fig. 4, valves 'lfland H are yieldably urged toward their port closing positions by coil springs I2 which engage collars 13- on the valve stems and adjustable'screws 1'4 threadedly received by the relief valve frames 15. Through the adjustment of screws 14 of the relief valves, the'tension on springs 12- may be varied? to change the pressures at which fluid will be permitted to flow through bypass ports GI and B5. Suitable housing means I6 are provided to protect the relief valves 63 and 61 from unauthorized adjustment;

In the operation of the pressure generating unit, both pumps supply fluid to be used in the system until a certain pressure has been reached in chamber 41, at which time, valve 55 will seat to, prevent fluid underhigher pressure. from flowing into section 5! and being; bypassed through port Ell to the reservoir. In the event the system supplied by the unit is fed through conduit 58' only, the entire output of pump 22' will be bypassed through the relief valve 63 when the pressure. in chamber section 58 exceeds that for which. valve 53 has previously been set. Fluid exhausted from the fluid motor or motors in the system is returned to the manifold through pipes 11 and 18. These pipes communicate with chamber 48 and fluid is conducted therefrom to the reservoir through the pipe 64.

This power unit is particularly useful in supplying:the motivating force for a machine 111001. in which a piston orother element is required to travel a considerable distance then develop or exert, a strong force during the final stage :of its .travel. When connected with such a machine, the high and low pressure pumps 22 and .;23;wil l together deliver a suflicient volume of fluidzto cause the moveable element to travel at the desired {rate and when the end of this travel is approached, and high fluid pressures are necessary to perform the useful work, these high pressures will be developed by thepump 23 which delivers a small volume of fluid at high pressure. Through the provision of the self closing, valve 55, the load of thishigh pressure will not be imposed on the low pressure pump. Valve 55 in such instance, will prevent the escape of fluid from chamber section 50 through the low pressure bypass and will thus make the power unit more eflicient. The mechanism may be employed as above described whereinvalve 55 is permittedto; open when pressures in chambersections 50 andjl are substantially equal or the pressure in the latter section exceeds that insection 50. valve isso set, communication may take place in a direction from section l -to section so that the low pressure high volume pur'npwill be permitted to supply-fluid to the portion of the system connected with pipe 58.

The mechanism may also be employed in a different combination in which stop 54 is adjusted tohold't'he valve in engagement with seat 52 and prevent communication between chamber sections 50 and 5|. When the stop is so adjusted, the effect, of separate pressuregenerating units will besecured, all the fluid supplied by the lowpressure pump being conducted from the manifold 25 to the portion of the system connecteditherewith through pipe 51 and the high pressure fluid flowing from the manifold through pipe 58,

A third combination is also possible wherein check valve 55 is removed and the flow' from pumps 22 and 23 combined. In this particular combination, the fluid from both pumps'will be bypassed to the reservoir through the low pressure relief valve 63 unless an adjustment is made in the setting of the high pressure relief valve 61. Both valves 63 and 61 should be set to operate at the same pressure.

From the foregoing, it will be seen that .a novel pressure. generating unit has been providedwhich is compact and efficient. It may be bodily removed from a hydraulic system, serviced and replaced without dismantling the system since the unit 20 is self contained and has been designed to be connected with a hydraulic system quickly and with a minimum expenditure of time and effort. I

A control panel 80 is provided at the rear of the unit to govern the operation of the motor 2 I if}, This panel may be equipped with any suitable means to effect the desired operation of the unit.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

I claim:

1. A fluid pressure unit comprising, in combination, a high volume low pressure pump; a low volume high pressure pump; means forming a manifold chamber communicating with the outlets of said pumps; valve means in said manifold chamber dividing the same into high and low pres- When this sure sections, said low and high pressure pumps communicating with said low and high pressure sections respectively, said valve means preventing fluid flow from said high to said low pressure section; said manifoldv having an outlet from each of said sections; and relief valves for'controlling fluid flow through'said last-mentioned outlets, said relief valves being responsive to different pressures. I

2. A fluid pressure generator comprising in combination, a prime mover; a pair of fluid pumps connected for operation with said prime mover a fluid supply source communicating with the inlets of said pumps; manifold means communicating with the outlets of said pumps, said manifold means vhaving a pair of outlets communicating with said. fluid supply source ;v relief valves for controlling fluid flow through said pair of outlets; and means in said manifold between the outlets to limit fluid flow therebetween to but one direction. p 3. A fluid pressure generator comprising in combination, a prime mover; a pair of fluidpumps connected for operation with said prime mover; a fluid supply source communicating with theinlets of said pumps; manifold means communicating at spaced points with the outlets of; said pumps; seat means in said manifold between the points of connection thereof with said pumps, said manifold having anoutlet on either side. of said seat communicating with said fluid supply source; relief valve means controlling fluid flow through said outlets; and valve means engaging said seat to restrict fluid flow thereby to but one direction.

4. A fluid pressure generator comprising in combination, a prime mover; a pair of fluid pumps connected for operation with said prime mover; a fluid supply source communicating with the inlets of said pumps; manifold means having a body provided with an internal chamber communicating at spaced points with the outlets of said pumps; a seat formed in said chamber between the points of connection thereof with said pumps; a valve; and means for resiliently urging said valve into engagement with said seat to prevent fluid flow therethrough to but a single direction.

5. A fluid pressure generator comprising, in combination, a motor; a reservoir for hydraulic fluid disposed above said motor; a pump positioned at each end of said motor and connected for operation therewith; means connecting the inlets of said pumps with said reservoir; a manifold having a chamber communicating at spaced points with the outlets of said pumps; a valve seat in said chamber between the points of communication with said pumps, said manifold having an outlet communicating with said reservoir, said outlets being disposed on either side of said seat; pressure responsive valve means for controlling fluid flow through said outlets; and a spring pressed valve engaging said valve seat, said valve limiting fluid flow through said chamher to but one direction.

6. A fluid pressure generator comprising, in combination, a motor; a reservoir for hydraulic fluid disposed above said motor; a pump positioned at each end of said motor and connected for operation therewith; said pumps having different pressure capacities; means connecting the inlets of said pumps with said reservoir; a manifold having a chamber communicating at spaced points with the outlets of said pumps; a valve seat in said chamber between the points of communication with said pumps, said manifold having an outlet communicating with said reservoir on each side: of said seat; valve means rsponsiv'ecto fluid pressures for controlling fiui'c'i-flow through said cutlets; the valve on-the same s ideof said" seat as the-iower pressure pump Being-responsive to lbwer 'pressu-re than the otherrand avalve mem- 'ite'r resiliently urged toward said valve' seat to prevem fluid flow'from said pressure pump tassel-war pressureouties i 7. A fluid pressure unit comprising, incom rnationhigh-volume low pressure pump; a low volume high pressure pump;- means forming a manifold'chamber communicating with the out let's' or said pumps; valve means in said manifold chamber dividing the same into high and low pressure sections, said low and high pressure pumps communicating with said low' and high pressure section respectively, said valve means preventing fluid flow from'said'high-to said low pressure section; and a pressure responsive relief valve for the high volume low pressure pump operable to relieve the pressure whenthe'} valve is closed and after the pressure created by the low pressure pump attains a'predetermined high value:

81A fluid pressureunit" comprising, in com pination; a high volume lovv pressure pump; a

:low volume high pressure pump; means forming a'manifold chamber communicating with the out lets of said pumps; valvemeans in said manifold chamber dividing the same into high and low pressure sections, said low and high' pressure pumps communicating with said low and high pressure sectionsrespectively, said valve means preventing fluid flow from said high to said low pressure section, each of said low and high pressure sections having an-outlet forsupplying fluid. R l v 9; A fluid pressure unit comprising, incombinaso I operable torelieve the pressure after the pressure determined hig-lr'value.

5 10. 'A fluidpressure unitcomprising, in combination, a'high volume low pressurepump; a low volume high pressure pump; means'forming'a created by the high pressure pump attains a premanifold chamber communicating with the outlets of said pumps'; valve means in said manifold chamber dividing the same into high and low pressure sections, 'saizil lovv a'nd' high pressure pumps communicating withsaid lowand high pressure sections respectivelysaid valve means preventingfiuidfiow from said high to said low pressure sectio'n; and pressure responsive relief valve means for one of said-pumps operable to relieve the pressure after the pressure created by said pump attains a predetermined high value. THOMAS EQB'AYMQNDI REFERENCES 1 CIT;ED

: The following references areiof in the file of. this; patent:

UNI'IED" STATES PATENTS Number Name' 4 I Date" f Losel' [1,523, 98 'Jan. 20, 1925 

